CH268783A - Process for the preparation of a chlorobenzoic acid amide. - Google Patents

Description

       

  Process for the preparation of a chlorobenzoic acid amide. In the fight against the insect plague, agents are usually used that poison the insects and thus kill them. In many cases, however, agents are also used which drive away the insects, namely the flies and mosquito species that often carry pathogens, so that the insects do not cause any nuisance or contact with the pathogens. For example, dialkyl phthalates have been proposed as insect-repellent agents, but these have only a short-term effect.



  It was. now found that chlorobenzoic acid amides of the formula
EMI0001.0012
    where Z is a. Hydrogen or a chlorine atom and R an ethyl or allyl radical, have long-lasting insect-repellent properties and also show no harmful effects when used for warm-blooded animals. The compounds of the above formula are new.



  The defined chlorobenzoic acid a.mide can be made by methods known per se, in particular by adding a chlorobenzoic acid of the formula
EMI0001.0018
    or a salt or a reactive functional derivative thereof with an amine of the formula H-1 \ T (R.) "a salt or a reactive derivative thereof according to the equation
EMI0001.0020
    implements.

    In the simplest case, the free acid is heated with the amine, with water splitting off (Y = OH, Y '= H). Acid halides or anhydrides can be reacted with the amine, if desired in the presence of acid-binding agents, for which the amine itself can also be used (e.g. Y = Cl, Y '= H or Y = O-ayl, Y '= H). In addition, acid halides or anhydrides can also be reacted with metal compounds of amines (e.g. Y = Cl, Y '= Na) or, in special cases, acid halides with halogen hydrates of amines (e.g.

   Y = Cl, Y '= HCl. H, Y Y '= 2 HCl). When heated, esters react with the amines, splitting off alcohols (e.g. Y. =, OCHS, Y '= H), and finally certain amides also react with the amines or their salts (e.g.

   Y = NH ,, Y '= H). A special variant, which also proceeds according to the above reaction scheme, is the reaction of salts of the acid with reactive carbamic acid derivatives of the defined amines.

    For example, carbamic acid chlorides, which can also be classified as chloroformic acid derivatives of the secondary amines, can be reacted with alkali salts of the acids by heating with the elimination of carbon dioxide and alkali halide to give the desired amides (e.g.

   Y = ONa, Y '= Cl-CO-; YY '= NaCl + CO_). In a similar way, arylsulfonyl derivatives of amine can be reacted with chlorobenzoic acid or its salts by heating (e.g.

   Y = ONa, Y '_ SOZ-C, H $ CH3 (p), YY' = (p) CH @ S03Na). The preferred method is to react the acid chloride with the amine according to the equation:
EMI0002.0039
    The chlorobenzoic acid amides described have an insect-repellent effect.

   This is understood to mean that they are used to keep a large number of stinging, biting, blood-sucking or otherwise annoying humans and animals, and possibly disease-transmitting arthropods. are suitable. For example, the defined chlorobenzaeamides are effective against aedines, culicides, stinging flies, house flies and bed bugs.



       The present patent now relates to a process for the preparation of a chlorobenzoic acid amide. The process is characterized in that it is a compound of the formula
EMI0002.0061
    with a compound of the formula
EMI0002.0063
    where Y and Y 'are radicals which split off in the reaction.



  The new compound obtained, the 2-chloro-benzoic acid diethylamide, is a colorless oil with a boiling point of 125-128 under 0.4 mm pressure and crystallizes in prisms with a melting point of 39-40. It should serve as an insect repellent.

      <I> Example 1: </I> 17.5 parts of o-chloro-benzoyl chloride, produced. from o-chloro-benzoic acid and thionyl chloride, are slowly cooled to a solution of 150 parts abs. Benzene and 1.4 parts of diethylamine given. After stirring for 1 hour at room temperature, the separated diethylamine chlorohydrate is filtered off with suction, washed with a little benzene and the benzene evaporated.

   On distillation, the residue gives a colorless, slightly viscous oil of boiling point 4 125-1281, which soon stiffens. The 2-chloro-benzoic acid diethylamide can be obtained in colorless prisms with a melting point of 39-40 by recrystallizing from petroleum ether.

      <I> Example 2: </I> 17.5 parts of o-chloro-benzoylechloride, produced by chlorinating o-chloro-benzaldehydes, are converted into a slurry of 6 parts of soda cale at room temperature. in a solution of 7 parts of diethylamine in <B> 150 </B> parts of dry benzene.

   After three hours of refluxing, the benzene solution is washed with dilute hydrochloric acid and then with dilute sodium hydroxide solution and water, dried over sodium sulfate and the residue is distilled in vacuo after the benzene has been evaporated.

    2-Chloro-benzoic acid diethylamide with a melting point of 30-40 is obtained in good yield. Example <I> 3: </I> 85 parts of o-chloro-benzoic acid-niethylester, 37 parts of diethylamine 1.00% and 200 parts of dry benzene are heated together in a steel autoclave to 100-110 for 6 hours.

   The liquid reaction product is washed successively with 2N hydrochloric acid, 2N sodium hydroxide solution and water, the benzene is evaporated and the residue is distilled in vacuo. After separating off a little unchanged ester, 2-chloro-benzoic acid-diethylamide is obtained at bp 164-165. <I> Example 4: </I> In a 500 cm3 round bottom flask with a ground joint cooler, 89 parts of 2-chlorobenzoesa.ures sodium are mixed with 73 parts of dietary carbamic acid chloride and slowly heated in an oil bath.

   At about 150, a reaction takes place with the escape of carbon dioxide. After the temperature was kept at 150-160 for a further 3 hours, the mass is diluted with water and the reac tion product obtained by etherification. After the usual cleaning of the ethereal solution with dilute hydrochloric acid and dilute sodium hydroxide solution, the ethereal solution is dried and the ether is evaporated. The distillation of the residue gives the 2-chloro-benzoic acid diethylamide at bp "" 125-127.



       Example <I> 5: </I> 16 parts of o-chloro-benzoic acid are mixed with 25 parts of p-toluene-N-diethyl-sulfamide in an open round-bottom flask and heated to about <B> 21500 </B> The diethyl zmido group is exchanged after an exothermic reaction. After cooling, the toluenesulfonic acid can be extracted with water and the 2-chlorobenzoic acid diethylamide from the solid residue by recrystallization from benzene petroleum ether

  Gain melting point 39-40.


    

Claims (1)

PATENT CLAIM Process for the preparation of a chlorobenzoic acid amide, characterized in that a compound of the formula EMI0003.0045 with a compound of the formula EMI0003.0046 where Y and Y 'see radicals which split off during the reaction are converted. The new compound obtained, the 2-chloro-benzoic acid diethylamide, is a colorless oil with a boiling point of 125-128 under 0.4 mm pressure and crystallizes in prisms with a melting point of 39-40. SUBCLAIMS 1. Process according to patent claim, characterized in that o-chloro-benzoyl chloride is reacted with diethylamine. 2. The method according to patent claim, characterized in that a salt of 2-chloro-benzoic acid is reacted with diethylcarbamic acid chloride. 3. The method according to claim, characterized in that an o-chlorobenzoic acid ester is reacted with diethylamine.